Research On Rutting Development Regulation Of Asphalt Mixture Based On FBG And Numerical Simulation

With the rapid rise of Chinese economic strength,the number of car ownership is growing rapidly,and highway construction is also booming.Asphalt pavement,as the main pavement type of Expressway in China,has many advantages,but its shortcomings are obvious.Rutting is one of the most important and serious problems in the early diseases of asphalt pavement.It is very difficult to treat and harmful once it is formed.Therefore,based on FBG technology and finite element method,this paper makes further research on the development law of asphalt mixture rutting.Through previous studies,it is found that the double-layer rutting test can take into account the influence of structural combination on the rutting resistance of asphalt pavement,and the test results are good.When studying the rule of rutting development,dynamic stability can be used to evaluate the high temperature stability of asphalt mixture,but the key is to control the variation of stress and strain in pavement structure.For the application of fiber Bragg grating sensors in pavement health monitoring,various composite materials are used to encapsulate the sensors and measure the three-dimensional strain in asphalt mixture,while the transverse strain law on the surface of the sensors is seldom studied.Therefore,in this paper,surface-mounted fiber grating sensors are used to monitor the specimens with and without anti-rutting agents.The transverse strain data of asphalt mixture on the surface of the specimens are collected,and the rutting mechanism and development law are analyzed by ABAQUS finite element software simulation.The main conclusions are as follows:(1)The average dynamic stability of rutting slab with anti-rutting agent is 3552 times/mm,and that of rutting slab without anti-rutting agent is 2369 times/mm.Therefore,adding anti-rutting agent can improve the dynamic stability of asphalt mixture.(2)At the end of the double-layer rutting test,the asphalt mixture of the upper layer has reached a relatively stable state,while the lower layer may not reach a stable state.In the test of adding anti-rutting agent,the maximum compressive strain of the upper layer reaches 1242με and that of the lower layer reaches 582με.In the test without anti-rutting agent,the maximum compressive strain of the upper layer reaches 723με and the maximum compressive strain of the lower layer reaches 1738με.It shows that the strain of the lower layer is large without anti-rutting agent,and the strain of the upper layer is large after adding anti-rutting agent.(3)Combining the indoor rutting test and the finite element simulation results,it is found that thevertical deformation at the wheel track of the upper plate is obviously larger than that of the lower plate.The strain variation law of asphalt mixture on the rutting surface along the vertical groove direction is as follows: the upper layer presents the rule of "compression strain-tension strain-compression strain",and the compression strain tends to zero at last;the lower layer presents the rule of "tension strain-compression strain",and the compression strain tends to zero finally.(4)Through the finite element simulation of indoor rutting test,it is found that the "rule of transverse strain variation of asphalt mixture along the vertical rutting direction" is consistent with the conclusion obtained from the test data.The addition of Anti-rutting agent and the increase of the thickness of rutting plate specimens will have an impact on this rule.The results of this paper can better reflect the change law of transverse strain of asphalt mixture surface,and study the influence of mixing anti-rutting agent and structure combination design on rutting development law,which can provide reference for practical engineering and application.